Information About Using the Command-Line Interface

Command Modes

The Cisco IOS user
interface is divided into many different modes. The commands available to you
depend on which mode you are currently in. Enter a question mark (?) at the
system prompt to obtain a list of commands available for each command mode.

You can start a CLI
session through a console connection, through Telnet, an SSH, or by using the
browser.

When you start a
session, you begin in user mode, often called user EXEC mode. Only a limited
subset of the commands are available in user EXEC mode. For example, most of
the user EXEC commands are one-time commands, such as
show commands,
which show the current configuration status, and
clear commands,
which clear counters or interfaces. The user EXEC commands are not saved when
the
switch
reboots.

To have access to all
commands, you must enter privileged EXEC mode. Normally, you must enter a
password to enter privileged EXEC mode. From this mode, you can enter any
privileged EXEC command or enter global configuration mode.

Using the configuration
modes (global, interface, and line), you can make changes to the running
configuration. If you save the configuration, these commands are stored and
used when the
switch
reboots. To access the various configuration modes, you must start at global
configuration mode. From global configuration mode, you can enter interface
configuration mode and
line configuration mode
.

This table describes
the main command modes, how to access each one, the prompt you see in that
mode, and how to exit the mode.

Table 1. Command Mode
Summary

Mode

Access Method

Prompt

Exit Method

About This Mode

User EXEC

Begin a session
using Telnet, SSH, or console.

Switch>

Enter
logout or
quit .

Use this mode to

Change
terminal settings.

Perform
basic tests.

Display
system information.

Privileged EXEC

While in user
EXEC mode, enter the
enable command.

Switch#

Enter
disable to exit.

Use this mode to
verify commands that you have entered. Use a password to protect access to this
mode.

Use this mode to execute
privilege EXEC commands for access points. These commands are not part of the
running config of the controller, they are sent to the IOS config of the access
point.

Global
configuration

While in
privileged EXEC mode, enter the
configure
command.

Switch(config)#

To exit to
privileged EXEC mode, enter
exit or
end , or press
Ctrl-Z.

Use this mode to
configure parameters that apply to the entire
switch.

Use this mode to configure
access point commands that are part of the running config of the controller.

VLAN
configuration

While in global
configuration mode, enter the
vlan vlan-id command.

Switch(config-vlan)#

To exit to
global configuration mode, enter the
exit command.

To return to
privileged EXEC mode, press
Ctrl-Z or
enter
end .

Use this mode to
configure VLAN parameters. When VTP mode is transparent, you can create
extended-range VLANs (VLAN IDs greater than 1005) and save configurations in
the
switch
startup configuration file.

Interface
configuration

While in
global configuration mode, enter the
interface
command (with a specific interface).

Switch(config-if)#

To exit to
global configuration mode, enter
exit .

To return to
privileged EXEC mode, press
Ctrl-Z
or enter
end .

Use this mode
to configure parameters for the Ethernet ports.

Line
configuration

While in
global configuration mode, specify a line with the
line vty or
line console
command.

Switch(config-line)#

To exit to
global configuration mode, enter
exit .

To return to
privileged EXEC mode, press
Ctrl-Z
or enter
end .

Use this mode
to configure parameters for the terminal line.

Understanding
Abbreviated Commands

You need to enter only
enough characters for the
switch
to recognize the command as unique.

This example shows how
to enter the
show configuration privileged EXEC command in an
abbreviated form:

Switch# show conf

No and Default Forms of Commands

Almost every configuration command also has a no form. In
general, use the no form to disable a feature or function or
reverse the action of a command. For example, the no shutdown
interface configuration command reverses the shutdown of an interface. Use the command
without the keyword no to reenable a disabled feature or to
enable a feature that is disabled by default.

Configuration commands can also have a default form. The
default form of a command returns the command setting to
its default. Most commands are disabled by default, so the
default form is the same as the no
form. However, some commands are enabled by default and have variables set to certain
default values. In these cases, the default command enables the
command and sets variables to their default values.

CLI Error Messages

This table lists some error messages that you might encounter while using the CLI to configure your switch.

Table 2. Common CLI Error Messages

Error Message

Meaning

How to Get Help

% Ambiguous command: "show con"

You did not enter enough characters for your switch to recognize the command.

Reenter the command followed by a question mark (?) without any space between the command and the question mark.

The possible keywords that you can enter with the command appear.

% Incomplete command.

You did not enter all of the keywords or values required by this command.

Reenter the command followed by a question mark (?) with a space between the command and the question mark.

The possible keywords that you can enter with the command appear.

% Invalid input detected at ‘^’ marker.

You entered the command incorrectly. The caret (^) marks the point of the error.

Enter a question mark (?) to display all of the commands that are available in this command mode.

The possible keywords that you can enter with the command appear.

Configuration Logging

You can log and view changes to the switch configuration. You can use the Configuration Change Logging and Notification feature to track changes on a per-session and
per-user basis. The logger tracks each configuration command that is applied, the user who entered the command, the time that
the command was entered, and the parser return code for the command. This feature includes a mechanism for asynchronous notification
to registered applications whenever the configuration changes. You can choose to have the notifications sent to the syslog.

Note

Only CLI or HTTP changes are logged.

Using the Help
System

You can enter a
question mark (?) at the system prompt to display a list of commands available
for each command mode. You can also obtain a list of associated keywords and
arguments for any command.

Procedure

Command or Action

Purpose

Step 1

help

Example:

Switch# help

Obtains a brief
description of the help system in any command mode.

Step 2

abbreviated-command-entry?

Example:

Switch# di?
dir disable disconnect

Obtains a list of
commands that begin with a particular character string.

Step 3

abbreviated-command-entry
<Tab>

Example:

Switch# sh conf<tab>
Switch# show configuration

Completes a
partial command name.

Step 4

?

Example:

Switch> ?

Lists all commands
available for a particular command mode.

Step 5

command
?

Example:

Switch> show ?

Lists the
associated keywords for a command.

Step 6

command keyword
?

Example:

Switch(config)# cdp holdtime ?
<10-255> Length of time (in sec) that receiver must keep this packet

Lists the
associated arguments for a keyword.

How to Use the CLI to Configure Features

Configuring the Command History

The software provides a history or record of commands that you have entered. The command history feature is particularly useful
for recalling long or complex commands or entries, including access lists. You can customize this feature to suit your needs.

Changing the Command History Buffer Size

By default, the switch records ten command lines in its history buffer. You can alter this number for a current terminal session or for all sessions
on a particular line. This procedure is optional.

Procedure

Command or Action

Purpose

terminal history [size number-of-lines]

Example:

Switch# terminal history size 200

Changes the number of command lines that the switch records during the current terminal session in privileged EXEC mode. You can configure the size from 0 to 256.

Recalling Commands

To recall commands from the history buffer, perform one of the actions listed in this table. These actions are optional.

Note

The arrow keys function only on ANSI-compatible terminals such as VT100s.

Procedure

Command or Action

Purpose

Step 1

Ctrl-P or use the up arrow key

Recalls commands in the history buffer, beginning with the most recent command. Repeat the key sequence to recall successively
older commands.

Step 2

Ctrl-N or use the down arrow key

Returns to more recent commands in the history buffer after recalling commands with Ctrl-P or the up arrow key. Repeat the key sequence to recall successively more recent commands.

Step 3

show history

Example:

Switch# show history

Lists the last several commands that you just
entered in privileged EXEC mode. The number of commands that appear is controlled by the setting of
the terminal history global configuration command
and the history line configuration command.

Disabling the Command History Feature

The command history feature is automatically enabled. You can disable it for the current terminal session or for the command
line. This procedure is optional.

Procedure

Command or Action

Purpose

terminal
no history

Example:

Switch# terminal no history

Disables the feature during the current terminal session in privileged EXEC mode.

Enabling and Disabling Editing Features

Although enhanced editing mode is automatically enabled, you can disable it and reenable it.

Procedure

Command or Action

Purpose

Step 1

terminal editing

Example:

Switch# terminal editing

Reenables the enhanced editing mode for the current terminal session in privileged EXEC mode.

Step 2

terminal no editing

Example:

Switch# terminal no editing

Disables the enhanced editing mode for the current terminal session in privileged EXEC mode.

Editing Commands
Through Keystrokes

The keystrokes help
you to edit the command lines. These keystrokes are optional.

Note

The arrow keys
function only on ANSI-compatible terminals such as VT100s.

Table 3. Editing
Commands

Editing Commands

Description

Ctrl-B or use the
left
arrow key

Moves the
cursor back one character.

Ctrl-F or use the
right
arrow key

Moves the
cursor forward one character.

Ctrl-A

Moves the
cursor to the beginning of the command line.

Ctrl-E

Moves the
cursor to the end of the command line.

Esc B

Moves the
cursor back one word.

Esc F

Moves the
cursor forward one word.

Ctrl-T

Transposes the
character to the left of the cursor with the character located at the cursor.

Delete or
Backspace key

Erases the
character to the left of the cursor.

Ctrl-D

Deletes the
character at the cursor.

Ctrl-K

Deletes all
characters from the cursor to the end of the command line.

Ctrl-U or
Ctrl-X

Deletes all
characters from the cursor to the beginning of the command line.

Ctrl-W

Deletes the
word to the left of the cursor.

Esc D

Deletes from
the cursor to the end of the word.

Esc C

Capitalizes at
the cursor.

Esc L

Changes the
word at the cursor to lowercase.

Esc U

Capitalizes
letters from the cursor to the end of the word.

Ctrl-V or
Esc
Q

Designates a
particular keystroke as an executable command, perhaps as a shortcut.

Return key

Scrolls down a
line or screen on displays that are longer than the terminal screen can
display.

Note

The More
prompt is used for any output that has more lines than can be displayed on the
terminal screen, including
show command
output. You can use the
Return and
Space bar keystrokes whenever you see the More prompt.

Space bar

Scrolls down
one screen.

Ctrl-L or
Ctrl-R

Redisplays
the current command line if the
switch suddenly sends a message to your
screen.

Editing Command Lines That Wrap

You can use a wraparound feature for commands that extend beyond a single line on the screen. When the cursor reaches the
right margin, the command line shifts ten spaces to the left. You cannot see the first ten characters of the line, but you
can scroll back and check the syntax at the beginning of the command. The keystroke actions are optional.

To scroll back to the beginning of the command entry, press Ctrl-B or the left arrow key repeatedly. You can also press Ctrl-A to immediately move to the beginning of the line.

Note

The arrow keys function only on ANSI-compatible terminals such as VT100s.

The following example shows how to wrap a command line that extends beyond a single line on the screen.

When the cursor first reaches the end of the line, the line
is shifted ten spaces to the left and redisplayed. The dollar sign ($) shows that the line
has been scrolled to the left. Each time the cursor reaches the end of the line, the line
is again shifted ten spaces to the left.

Example:

The dollar sign ($) appears at the end of the line to show that the line has been scrolled to the right.

Step 3

Return key

Execute the commands.

The software assumes that you have a terminal screen that is 80 columns wide. If you have a
different width, use the terminal width privileged EXEC
command to set the width of your terminal.

Use line wrapping with the command history feature to recall and modify previous complex command entries.

Searching and Filtering Output of show and more Commands

You can search and filter the output for show and
more commands. This is useful when you need to sort through
large amounts of output or if you want to exclude output that you do not need to see. Using
these commands is optional.

Procedure

Example:

Switch# show interfaces | include protocol
Vlan1 is up, line protocol is up
Vlan10 is up, line protocol is down
GigabitEthernet1/0/1 is up, line protocol is down
GigabitEthernet1/0/2 is up, line protocol is up

Searches and filters the output.

Expressions are case sensitive. For example, if you enter | exclude
output , the lines that contain output are not
displayed, but the lines that contain output appear.

Accessing the CLI
on a Switch Stack

You can access the CLI
through a console connection, through Telnet, a SSH, or by using the browser.

You manage the switch
stack and the stack member interfaces through the
active switch. You cannot manage stack members on an
individual switch basis. You can connect to the
active switch through the console port or the Ethernet
management port of one or more stack members. Be careful with using multiple
CLI sessions on the
active switch. Commands that you enter in one session
are not displayed in the other sessions. Therefore, it is possible to lose
track of the session from which you entered commands.

Note

We recommend using
one CLI session when managing the switch stack.

If you want to configure
a specific stack member port, you must include the stack member number in the
CLI command interface notation.

To debug the standby switch,
use the
session standby ios privileged EXEC command from the active switch to access the IOS
console of the standby switch. To debug a specific stack member, use the
session switch stack-member-number privileged EXEC command from
the active switch to access the diagnostic shell of the stack member. For more
information about these commands, see the switch command reference.

Accessing the CLI
Through a
Console Connection or Through Telnet

Before you can access
the CLI, you must connect a terminal or a PC to the
switch
console
or connect a PC to the
Ethernet management port
and then power on the
switch,
as described in the hardware installation guide that shipped with your
switch.

If your
switch
is already configured, you can access the CLI through a local console
connection or through a remote Telnet session, but your
switch
must first be configured for this type of access.

You can use one of
these methods to establish a connection with the
switch:

Procedure

Connect the
switch
console port to a management station or dial-up modem, or connect the Ethernet
management port to a PC. For information about connecting to the
console or Ethernet management
port, see the
switch
hardware installation guide.

Use any Telnet
TCP/IP or encrypted Secure Shell (SSH) package from a remote management
station. The
switch
must have network connectivity with the Telnet or SSH client, and the
switch
must have an enable secret password configured.

The
switch
supports up to 16 simultaneous Telnet sessions. Changes made by one Telnet user
are reflected in all other Telnet sessions.

The
switch
supports up to five simultaneous secure SSH sessions.

After you connect
through the console port,
through the
Ethernet management port,
through a Telnet session or through an SSH session, the
user EXEC prompt appears on the management station.